Dial foot soldering

[watchweasol]

Hi Working on a seiko 7009A today, a bit of a wreck. Dial loose intermediate date wheel u/s, all back up and running but had to sort out the dial so I dug out the dial foot machine build a couple of years ago, as you can see by the pics it still works and no marking on the dial. It was build from readily available parts. The power source is a car battery charger which plugs into the unit. the probe is the carbon center core from a battery. I belive it goes under the heading of cold soldering, basicaly it provides an arc at the bottom of the dial foot wire where you place some flux and bits of solder. the resulting arc melts the solder and attaches the foot wire. Any body interested can find the details on the net. The origionator of this particular design was one Dirk Fassbender the details he put on the net are still there or alternativly there is a book,  Quartz watch retro fitting  by Wesley R Door, available in America but not so easy over here in the uk. I have some pictures I copied from the net that give the basics. All it is is a transformer providing the Arc not hard to build and a very hand tool to have in your collection.. 

[stevew]

Interesting, but rare having to do dial feet. Soldering iron does job.

[jdm]

1 hour ago, stevew said:

Interesting, but rare having to do dial feet. Soldering iron does job.

 It's quite common on these Seiko. I would not dare or recommed to use a soldering iron.

[AndyHull]

I haven't done any dial feet soldering, but I have done quite a lot of electronic soldering over the years.

You might also be interested in low temperature solders.

https://www.digikey.com/en/product-highlight/c/chip-quik/low-temperature-indium-solder-wire

Keeping the heat as local as possible helps, when working with sensitive components, as does careful heat sinking and using suitable fluxes to minimise soldering time.

[teegee]

I've been experimenting with a similar setup too, using a 10A DC power supply and carbon rod, minus the nice case. Not sure what's wrong, but I just couldn't get anything to stick to the dial, with various fluxes (resin core, electronics type flux, nasty plumber flux). It seems like the dial doesn't get hot enough through thermal conductivity via the dial foot wire.

[measuretwice]

15 hours ago, teegee said:

I've been experimenting with a similar setup too, using a 10A DC power supply and carbon rod, minus the nice case. Not sure what's wrong, but I just couldn't get anything to stick to the dial, with various fluxes (resin core, electronics type flux, nasty plumber flux). It seems like the dial doesn't get hot enough through thermal conductivity via the dial foot wire.

Perhaps not enough current.  Any sense of the voltage/ current you are getting?  very low voltage high current is  the usually way to make a resistance solderer.  A great way is to take the secondary off a microwave transformer and replace it with a few loops of that super thick speaker wire some audiophiles love (little do they know it only sounds different because you've added capacitance lol).

I've got one that's half built, I used the rack and pinion from an old microscope as a way to move the pin into perfect perpendicular contact with the dial.  A sponge sits under the deal to insure the heat doesn't affect the dial face.  Pics to follow.

Oh, carbon rods are readily available in different diameters at welding supply places - just ask for carbon gouging rod

 

 

[nickelsilver]

I haven't done much with these but I found that anything other than copper for the foot just didn't work. German silver, brass, no. Copper, surprisingly well.